<!DOCTYPE HTML>
<html lang="en">
 <head>
  <meta charset="utf-8">
  <title>Workers example: Multiviewer</title>
  <script>
   function openViewer() {
     window.open('viewer.html');
   }
  </script>
 </head>
 <body>
  <p><button type=button onclick="openViewer()">Open a new
  viewer</button></p>
  <p>Each viewer opens in a new window. You can have as many viewers
  as you like, they all view the same data.</p>
 </body>
</html>
